An apparatus for submental electrical stimulation of the supra hyoid muscles at the floor of mouth with an electrode is known from German document 297 12 412 U1. The electrode is designed to be arranged below the tongue on the mucous membrane covering the floor of mouth. The electrode at its bottom side includes an electrically conductible surface portion. The known apparatus includes a support for the electrode, the support being designed to arrange the electrode below the tongue on the mucous membrane covering the floor of mouth. The support may be designed to be supported at the set of teeth close to the floor of mouth. Preferably, it includes an individually adapted connecting plate for this purpose. Preferably, the electrode is designed as a surface electrode approximately covering the entire region of the supra hyoid muscles to be stimulated. In other words, the known electrode covers the entire inner region of the front part of the floor of mouth.
When using the known apparatus, it has been found that the surface electrode being located below the tongue only attains surface contact to the floor of mouth when there is high pressure acting upon the electrode to be presses against the soft floor of mouth. This also applies when the surface electrode is made of flexible material. In addition, when using the known apparatus, there will be undesired overstimulation of the frenulum of tongue. Consequently, carrying and using the known apparatus is not convenient to the patient. As a result, application of the known apparatus is either stopped, or it results in undesired effects without reliably achieving the desired results. These drawbacks are increased since the known apparatus is used without supervision by professional staff.
Another apparatus for submental electrical stimulation of the supra hyoid muscles at the floor of mouth with an electrode is known from U.S. Pat. No. 5,190,053. The known apparatus includes two electrodes. The two electrodes are separately connected to a common deep-drawn bar from which they extend across the floor of mouth in a fixed arrangement such that the conductible surface portions of the two electrodes contact the frenulum of tongue from both sides. The bottom sides of the electrodes are coordinated with the anatomic shape of the edge portion of the floor of mouth which they contact. In an alternative embodiment of the known apparatus, the electrodes are not coordinated with the anatomic shape. For secure contact of their electrically conductible surface portions with the floor of mouth, this alternative embodiment of the known apparatus includes spring elements engaging the common deep-drawn bar and one of the electrodes. The spring elements elastically press the electrodes towards the floor of mouth. Both alternative embodiments of the known apparatus show two substantial drawbacks. First, the electrically conductible surface portions of the electrodes are only located in the edge portions of the floor of mouth. Thus, they only extend over a comparatively small portion of the floor of mouth even in a direction parallel to the frenulum of tongue. Second, the electrodes of the known apparatus even in the embodiment including elastic support at the deep-drawn bar cannot freely yield during conventional movement of the floor of mouth caused by varying muscle tension. While the strongly limited electrically conductible surface portions result in limited effectivity of the known apparatus, support of the electrodes even in a vertical direction—meaning perpendicular to the bite plane of the lower jaw—result in substantial restriction of carrying convenience for the patient who uses the known apparatus.